Pennsylvania Superior Court last week overturned the priest's 2012 conviction for mishandling reports of child sex abuse in the Archdiocese of Philadelphia

District Attorney Seth Williams filed paperwork to reargue the case against Monsignor William Lynn, a convicted Catholic priest who was awarded a new trial last week by a Pennsylvania appeals court.

Williams formally announced on Monday his intention to challenge the Pennsylvania Superior Court's ruling, saying he is prepared to appeal the case all the way to the state Supreme Court, if necessary, before returning to trial in Philadelphia.

"I think that we have to do all that we can to show Philadelphians that we're going to protect Philadelphians, especially when an institution uses institutional power to shield pedophiles," Williams said. "Hopefully, this will shed light on that and will show other people you can't do that."

A Pennsylvania Superior Court panel ruled, 2-1, that Lynn did not receive a fair trial when he was convicted of mishandling reports of child sex crimes. The court ruled the trial judge allowed jurors to hear too much evidence about the wrongdoing of priests who had abused children.

"I find it ironic that this Superior Court panel ruled that using all of the evidence was, in fact, too much evidence," Williams said. "We will continue to fight to keep Monsignor Lynn in state custody, where he belongs."

Williams filed a petition Monday requesting all nine members of the Superior Court reconsider the panel decision granting a new trial. The Superior Court must respond to Williams' petition within 60 days.

At the time of his conviction, Lynn was the highest-ranking Catholic priest to face charges for covering up abuse by priests. His trial refocused attention on a sex abuse scandal that roiled the faithful across the United States and undermined the church's moral authority around the world.

The Survivors Network of those Abused by Priests (SNAP) released a statement praising Williams for his diligence in holding Lynn responsible.

"The potential deterrence effect of this case – encouraging whistle-blowing and discouraging cover-ups in child sex cases – cannot be overstated," SNAP Philly Director Karen Polesir said. "Nor can the case's healing impact – on the thousands of victims of the 136 publicly accused Philly predator priests and the dozens of other predators whose identities remain hidden – be overstated."

Lynn, who once oversaw the work of 800 priests in the Archdiocese of Philadelphia as secretary of the clergy, was sentenced in 2012 to three to six years in prison. Upon the Superior Court panel's decision, his attorney filed a petition seeking bail. The Court of Common Pleas has not yet addressed it.

The panel decision marks the second time that Lynn’s conviction was overturned. He was released from prison in 2013 after serving 18 months when a state appeals court found that he was not responsible for the welfare of children, a decision that the state’s highest court reversed.